This invention relates to a thin type electronic instrument equipped with a circuit base plate having an integrated circuit chip mounted thereon and various functional devices such as power source battery for supplying power to said circuit base plate, etc.
In recent years, various thin type electronic instruments have been developed by making thinner small electronic calculators, such as card type pocket calculators equipped with an integrated circuit chip and a power source for supplying power to said circuit between resin sheets and IC card having memory function and clock function, etc.
The power source to be used in the thin type electronic instruments as mentioned above is required to have a thickness which is 1 mm or less, and for that purpose, for example, in card type pocket calculators having no memory function, etc., a thin solar battery with a thickness of about 200 um is used as its power source battery. However, in a thin type electronic instrument equipped with memory function and clock function, if a solar battery is used as the power source, in absence of light source, electric generation is stopped, whereby no power is supplied to the memory circuit of the integrated circuit chip or the clock circuit, whereby troubles are caused in maintenance of memory or clock function. For this reason, as the power source battery used for a thin type electric instrument endowed with memory function such as the above IC card, etc., a flat battery capable of supplying always power has been demanded. For such demand, there has been proposed a flat battery with a structure having a generating element comprising a positive electrode sheet 3, a negative electrode sheet 4 and a separator 5 interposed between these sheets 3 and 4 housed between the positive and negative electrode terminal plates 1 and 2 opposed to each other functioning as both armoring and current collector, and also having an insulating sealing member 6 shaped in a frame at the peripheral portion of the above positive and negative electrode terminal plates 1 and 2 to seal that portion as shown in FIG. 5 (Japanese Unexamined Patent Publication No. 128232/1974claiming priority based on Convention Application No. 344,883 filed Mar. 26, 1973 in the United States).
In this connection, as the thin type electronic instrument having the above flat battery assembled therein, one having the structure shown in FIG. 6 has been known(Japanese Unexamined Patent Pablication No. 15396/1986). That is, in the Figure, 11 and 12 are upper and lower sheets opposed to each other comprising a synthetic resin. Between these sheets 11 and 12 is housed the circuit base plate 13 and the flat battery 14 shown in FIG. 5 as described above. On the surface of the above circuit base plate 13, there are mounted an integrated circuit chip, passive element such as condenser, etc., not shown. Also, the positive and negative electrode terminal plates 1 and 2 of the above flat battery 14 are connected through the lead terminals 15 and 16 having spring characteristic to the wiring (not shown) formed on the front and back surfaces of the above circuit base plate 13 so that power of said battery 14 can be supplied to the integrated circuit chip, etc., on the circuit base plate. Also, at the peripheral portion between the above upper and lower sheets 11 and 12, there is interposed a frame-shaped sealing sheet 17 to effect plastering between the respective upper and lower sheets 11 and 12 and the frame-shaped sheet 17 by heat fusion or through an adhesive, thereby sealing the circuit base plate 13 having the above integrated circuit chip, etc., mounted thereon and the flat battery 14.
However, when a thin type electronic instrument with a structure shown in FIG. 6 is applied for card type pocket calculator or IC card, an inevitable stress is applied during carrying or usage thereof, and consequently there has been the danger that the card may be warped to lose the inherent function of the card. Also, since connection between the flat battery 14 and the circuit base plate 13 having integrated circuit chip, etc., mounted thereon is effected by use of lead terminals 15 and 16 connected resiliently to the positive and negative electrode terminals 1 and 2 of the battery 14, if the thickness of the battery 14 is not changed, the film thickness of the thin type electronic instrument becomes thicker corresponding to the thickness of the respective terminals 15 and 16. However, since the thickness of the thin type electronic instrument is restricted, the battery 14 itself cannot be made thicker during use of the above lead terminals 15 and 16, namely it becomes difficult to enhance the discharging capacity of the battery. This makes it difficult for thin type electronic instrument to respond to usage for a long term. Further, in the instrument shown in FIG. 6, the integrated circuit chip mounted on the circuit base plate 13 and lead terminals 15, 16 form convex portions, and other sites concave portions, whereby such concave or convex unevenness appears on the surface of the upper and lower sheets 11, 12 as such, to ensue the problem that the appearance as a whole of the instrument is impaired.